Chain
AdjustmentNever adjust your drive chain so it has less than 25-30 mm of vertical
movement. If it is tight it will stretch and wear very quickly, put undue
load on wheel bearings and swingarm bearings, in the worst cases the chain
brakes and puts a hole in the crankcases or wears out gearbox bearings
and shafts. If in doubt give it more free play not less.

Fact or Fiction?Carbon fibre mufflers out-perform alloy or steel mufflers.
The answer of course is fiction. The only reason for the use of carbon
on mufflers is to reduce weight. Carbon fibre is used in many areas on
race bikes, purely for its strength and light weight.

Tyre RepairsHave you ever gone to throw a leg over your favourite mount and head
for the hills only to find you have a flat tyre? Worse still, it set you
back $300.00 and has only done 1000 km.

Well, thank God for tubeless tyres. Not only did it not deflate in one
miliisecond going through that 150 km plus sweeper last night, but it can
be repaired cheaply and safely. There are special plugs available to repair
the new generation of tyres as long as the puncture is a clean hole and
not a big gaping slash. Even the tyre rating doesn't drop much, and I have
seen some very game and probably broke enthusiasts use them on ride days
without tasting disaster ( I don't recommend trying that one though).

Another thing to be aware of with radial tubeless tyres is that the
PSI rating is normally much higher, eg 36 psi in the front and 40 psi in
the rear is a fairly common rating.

Spark Plugs

I'm sure that many of you at some stage have been given the sales pitch
on the horse power advantages of fitting brand X spark plugs. Take this
as a warning: don't be fooled. My own personal experience with motorcycles
would indicate that this line of approach can be very misleading.

In fact one manufacturer who we'll not name has been pushing this point
very strongly and I am yet to see any proof behind this statement. I'm
not saying that they are wrong, I just haven't seen any indication that
they are right. One thing is certain though, we've had some problems with
them. They have been the cause of many a misfire and they have a nasty
habit of breaking in two when trying to remove them, resulting in many
frustrating hours for us and many dollars for the customer.

Set out below is a guide to help you avoid all these problems and select
the correct plug for your bike. Sometimes you can use alternative plugs,
but you need to have an understanding of what the number on the plug means
to ensure you're not stepping outside the limits of your engine's requirements.
So the 1st rule is always go with the manufacturer's recommendations. The
second rule is if you have any doubt give us a bloody call and save yourselves
a lot of agro.

We recommend and use NGK plugs so the following explanations are applicable
to NGK only.

The 1st letter prefix refers to the thread type and socket hexagon size.
They range from 14mm thread down to 8 mm on the little 4 cylinder 250 imports.

The 2nd and 3rd letter prefix is the construction feature. eg P for
projected insulator nose, R for resistor type. The first number refers
to the heat range. This is probably the most important code because it
refers to the operating heat range and means that if you get it wrong serious
damage to the engine is eminent. With NGK plugs the higher the number the
colder the plug. Racing engines use cold plugs because they generate so
much heat. If you have a fowling problem, common on two strokes, using
a hotter plug can sometimes cure it. But if you're off to P.I. for a ride
day you need to put that colder plug back in it. Also note that on other
brands the heat range works the opposite, 5 is colder than 7 not hotter
eg, Champion plugs.

The next suffix letter is for thread reach, which is also where you
can come unstuck because if you choose a plug with a thread reach that's
too long then it puts an interesting impression in the top of the piston,
if it's too short then it won't reach inside the combustion chamber.

The next letter is again for construction features, eg P for platinum
ground electrode, GV for racing plugs made of nickel alloy and centre electrode
made of precious metals, S for copper core electrode etc, etc. Sometimes
there is another number at the end meaning the plug gap which it is set
at.

The following is a common motorcycle plug number:
DPR9EA-9
Explanation, 12mm thread 18mm plug socket, P for projected electrode,
R for resistor, heat range 9, E for 19mm thread reach, A for specials and
9 for .9mm plug gap.

And there you have it, clear as mud, eh?. Don't worry if you're confused;
as I said earlier the manufacturer has done all the hard work, so if you
stick to their recommendations you can't go wrong. If it's for a seriously
modified engine then your engine builder should know what you need to use.

Shell Optimax

The response to our last newsletter on fuel has been quite surprising,
so I thought I would put in some answers to commonly asked questions which
have been supplied to us by Shell for your benefit. You can also go to
www.shell.com.au/optimax and send in your feedback.

JettingOptimax is suitable for all engines designed to run on unleaded petrol.
The design of the cooling system should have no influence on the suitability
of the fuel used. Carburetor fed engines may need adjustment towards a
leaner mixture but fuel injected engines with lamda sensors adjust to the
higher density and are generally less sensitive to the fuel density changes.

Rich runningWhen a bike is not tuned correctly to handle the high density of Optimax
it may result in rich running. Not all bikes are effected, but carbureted
bikes are more likely to suffer from running too rich, especially if they
are used around town in stop-start situations. Some of the ways to overcome
the bike running too rich include changing the plug to a slightly hotter
grade (always consult the engine manufacturer), reducing the jet size on
the carburetor, changing the carburetor needle, or a combination of the
above. This will help the bike run well on Optimax and allow the rider
the benefits of the high octane fuel—more power, especially at the high
end and an advanced fuel additive to maximize engine cleanliness.

Scott Oiler

This thing has got to be one of the best products you’ll ever add to
your bike, both in terms of maintenance and money saved. What they do is
provide a constant flow of oil to the final drive chain, meaning it never
runs dry. Like any moving part where there is friction there’s wear, so
when your chain is dry it wears extremely quickly. Think of it this way,
how long would your engine last with 1 ltr of oil when it holds 4 ltr’s,
or with no oil at all. Either way - not very long. Chains are no different,
they require a constant supply of oil to keep everything well lubricated
and thus prevent excessive wear, maintain smoothness and comfort while
not putting unnecessary load on wheel bearings and gearbox’s, thus improving
fuel consumption.

I have customers who were replacing chains and sprockets every 18-20,000km,
who are now clocking up well over 40,000km. One guy reckons he’ll get a
least 50,000km out of this lot. At $195.00 for the oiler he is well and
truly ahead.

Of course if you need someone to fit it for you then allow another $80.00,
and you're still ahead. :)

Performance
Tuning.

Our inventory of machinery includes a flow bench which is used to measure
the performance of cylinder heads. In conjunction with the dyno we are
able to test all performance packages before releasing them on the market
to ensure the best all round rear wheel horsepower suitable for the road
or track. We have found this to be a very difficult task as most products
we have tested don't perform to our high standards.

User friendly road-going horsepower is our aim, as shown in AMCN
and Streetbike Magazine tests on various bikes, including our Bimota SB6
which produces 155HP at the rear wheel and yet is still very sociable and
forgiving. You might also care to read the ZX9R Hot-up
article.

Dirty Filters

Air filters are important, but I must say this is a little bit ridiculous.
In case you don't recognise it, it's a stock filter out of GSXR1000 with
24000 km on the clock. A bit more time on maintance and a little less on
polishing wouldn't go amiss here. Don't let your filter get like this -
clean it, or replace it if it's not re-usable.